Tissue fasteners and related insertion devices, mechanisms, and methods

ABSTRACT

A tissue fastener includes a bridge section and two cannulated leg sections. The tissue fastener is a single piece of material, and the material can be a bioabsorbable material. Each of the two leg sections can include at least one barb for resisting dislodgement from tissue after the fastener is inserted into tissue. The bridge can be flexible, and the leg sections can receive needles to allow insertion of the fastener into tissue from above a surface of the tissue. Various insertion devices and mechanisms are possible to deploy the fastener into a wound in a patient&#39;s skin from above the surface of and generally perpendicular to the skin.

CROSS-REFERENCE TO RELATED APPLICATION

This claims the benefit of and priority to Provisional U.S. PatentApplication Ser. No. 60/817,858, which was filed on Jul. 1, 2006, andthe entirety of the contents of this priority provisional patentapplication is incorporated herein by reference.

TECHNICAL FIELD

This invention relates to fasteners for apposing the two sides of anincision or cut in human skin and other tissue and, more particularly,to bioabsorbable fasteners and related insertion devices.

BACKGROUND INFORMATION

Sutures for closing incisions in human skin are well known. The suturesare applied by physicians using a needle to pull the suture materialthrough the two sides of the incision. The suture material is tied whichfastens or apposes the two sides to allow healing. The suture materialmay be non-absorbable such as silk, polyester, etc. or it may be formedfrom bioabsorbable materials such as polyglycolic acid polymers.Applying sutures in this way requires skill and dexterity. Also itexposes the operator to possible needle stick injury. For these reasonsand because of the time that it takes to apply sutures, other fastenershave been developed, the most popular of these being referred to asstaples.

Surgical staples are made of non-reactive metals and are strong enoughto hold the tissues together once the ends of the staple have been bentinward. Although staples are faster and safer to apply than sutures,they have disadvantages. Because they penetrate the epidermis and remainexposed on the surface of the skin, they (i) present an opportunity forinfection, (ii) the wound must be kept dry until the staples are removed(5-7 days), and (iii) the patient must return for removal which requiresanother device, is time consuming, inconvenient and can causediscomfort.

Recently staples have been made of bioabsorbable plastics so that theycan be applied below the skin and will not require removal. To havesufficient strength to penetrate the skin and secure the tissue, theplastic typically must be much larger in cross section than anequivalent metal staple. For example, a staple wire with diameter of0.65 mm in metal would need to have a diameter of 2.5 mm to have thesame bending or buckling strength if made of plastic. Hence, thebioabsorbable staples tend to be bulky and to occupy significant volumewithin the wound. In addition, the means of applying the plastic staplemay be complex.

U.S. Pat. No. 6,726,705 relates to a mechanical method and apparatus forfastening tissue.

SUMMARY OF THE INVENTION

There exists a need for a biodegradable or bioabsorbable fastener thatcan be easily deployed from above the incision or other wound and thatcan be used to close minimally invasive surgery incisions as short as 5mm and that will hold the tissue apposed, lie below the surface of theskin, and occupy a small volume within the wound.

In one aspect, the invention generally relates to a tissue fastenercomprising a bridge section and first and second leg sections. Thebridge section includes a first portion and a second portion. The firstleg section is integral with the bridge section and extends from thefirst portion of the bridge section. At least a portion of the first legsection defines a first lumen extending therethrough such that the firstleg section is cannulated. The second leg section also is integral withthe bridge section, and it extends from the second portion of the bridgesection. At least a portion of the second leg section defines a secondlumen extending therethrough such that the second leg section also iscannulated. The bridge section and the first and second leg sectionscomprise a single piece of material.

In accordance with this aspect of the invention, various embodiments arepossible. For example, the single piece of material can bebioabsorbable, and the bioabsorbable material can be a polyglycolic acidpolymer, a copolymer, or a blend of polymers. Also, each of the firstand second leg sections can include at least one barb, and the at leastone barb can be oriented in a direction away from the surface of tissueafter the tissue fastener is inserted into the tissue. In general, thebarbs are oriented to resist dislodgement from tissue after the tissuefastener is inserted into the tissue. In addition, the bridge sectioncan be sufficiently flexible to allow the first and second leg sectionsto spread angularly after the tissue fastener is inserted into tissue.And, a portion of each of the first and second leg sections can betapered. Also, the bridge section can include a frangible connector forreleasably connecting the bridge section to another tissue fastener.

In another aspect, the invention generally involves a tissue fasteningsystem comprising the tissue fastener described above and also aninsertion device for deploying the tissue fastener into tissue.

In accordance with this other aspect of the invention, variousembodiments also are possible. For example, the insertion device can bepart of a larger insertion mechanism that an operator (such as asurgeon) manually operates to move indirectly the insertion device todeploy the tissue fastener from above the tissue in a generallyperpendicular orientation in relation to the surface of the tissue.Also, the insertion device can include a first needle for insertion intothe first lumen of the cannulated first leg section and a second needlefor insertion into the second lumen of the cannulated second legsection, and these needles can be substantially parallel to each other.

In yet another aspect, the invention generally features a tissuefastening system comprising the above-described tissue fastener and aninsertion mechanism for deploying the tissue fastener into tissue. Theinsertion mechanism includes an insertion device, and the insertiondevice is utilized to deploy the tissue fastener from above andgenerally perpendicular to the tissue.

In still another aspect, the invention generally involves a tissuefastening system comprising the above-described tissue fastener, aninsertion device for deploying the tissue fastener into tissue, andcompressing forceps that include first and second arms where each of thearms includes a surface for contacting the tissue. The first and secondarms can include a pair of movable tissue compressing arms.

The present invention also generally relates to a cannulated fastenerdevice made from bioabsorbable plastic materials. Accordingly, thebioabsorbable fastener comprises two legs cannulated to receive aninsertion device (which can be at least partially metallic), each leghaving at least one barb oriented to resist retraction of the fastenerafter deployment into tissue. The two legs are connected by a flexiblebridge and initially oriented parallel to each other. The bridge may beformed from a bioabsorbable polymer that becomes flexible at bodytemperature and/or can be shaped in a manner, such as having arectangular cross-section, which bends easily and allows the legs tospread angularly after insertion.

A fastener according to the invention is designed to hold the tissue inapposition while remaining totally below the surface of the skin.Accordingly, one preferred target area for each leg is the deep surfaceof the dermis between 1 and 4 mm, and preferably between 2 and 3 mmdisplaced from the cut surface in one embodiment. After the opposingwalls of the wound (or other tissue slit or opening) are pulled apartand everted to expose the inner surface of each of the walls upward,needles or other sharp injection members of the insertion devicepenetrate the deep surface of the everted dermis and drive the fastenerand its barbs into the body of the dermal tissue from above the surfaceof the skin. After insertion of the bioabsorbable fastener, thedelivering needles are withdrawn, leaving the fastener within the tissueand the tissue is released to allow the skin to relax as the legs of theembedded fastener open outwardly. The resulting final orientation of theembedded fastener brings the barbs into tension when the two sides ofthe tissue are apposed and slightly everted with the fastener restingcompletely below the surface of the skin.

A fastener according to the invention is designed to occupy a smallvolume within the wound to promote wound healing. Accordingly, the legsof the bioabsorbable fastener are cannulated with very thin side wallshaving a radial thickness between 0.1 and 0.5 mm, for example, andpreferably between 0.2 and 0.3 mm in one embodiment. The thin walls ofthe legs are tapered inwardly at their distal ends so that they reducethe penetrating force needed to insert them into the tissue. Strength topenetrate human tissue is provided by an insertion device, which hasdual metallic needles in one embodiment, dimensioned so that they slideinto the two legs of the fastener and exit the tapered ends of each leg.The dual needles are sharpened at their distal ends thus providing asharp point for entry into the tissue to be apposed.

A fastener made according to the present invention holds the twoapposing tissues together by tension forces between the barbs at theends of each leg. A bioabsorbable material, such as a polyglycolic acidpolymer, a copolymer, or a blend of polymers, is chosen to havemechanical properties such that each cannulated leg has a tensilebreaking strength of 2.5 pounds or greater in one embodiment. Onebioabsorbable material is polyglycolide, which is also known aspolyglycolic acid or (PGA), and it has a glass transition temperature of35-40° C., which is sufficiently low to allow the fastener, especiallythe bridge structure connecting the two legs, to become flexible at bodytemperature. Since the present fasteners operate in tension, while otherstaples operate by their structural strength, compressive strength, orresistance to deforming, fasteners according to the present invention donot need to be as massive, thus reducing the volume of foreign materialin the wound.

Fasteners according to the invention are designed to be deployed fromabove the skin. Accordingly, one embodiment of the present inventionprovides specially adapted compressing forceps or presser feet that areused in conjunction with tissue manipulators to evert the tissues to beapposed and thereby turn them upwards and also to compress them to apredetermined dimension suitable for accepting the fastener. Thefastener, mounted on the insertion device, then may be manually driveninto the tissue in the predetermined space between the compressingforceps. In an alternate embodiment, the compressing forceps can be usedin conjunction with a stapler-like device to deploy the fasteners. Thestapler-like device may be manually positioned with respect to thecompressing forceps using indexing pins or other features suitable formechanically referencing one part to another.

Fasteners according to the invention are designed to be deployed easilyand reproducibly without requiring special dexterity. An insertionmechanism may be used (in conjunction, for example, with tissuemanipulators) to provide a way to reproducibly position the surfaces ofthe dermal layer and to deploy the fastener. The insertion mechanismdesireably is able to carry multiple fasteners of the present invention,and comprises a means for loading the fasteners one at a time onto theinsertion device by passing the sharpened needles of the insertiondevice through the legs of the fastener. Alternatively, the insertionmechanism can carry a cartridge of insertion devices each pre-loadedwith a bioabsorbable fastener of the present invention, and means formoving the insertion devices one at a time into the translatingmechanism to drive into the tissue and then retract the insertion devicethereby leaving the fastener in place. The insertion mechanism has twofeatures (indentations or slots) into which two manipulators arepositioned, each having pinched one side of the tissue to be apposed.Tissue compressing arms, located on either side of the insertionmechanism, move in unison when the user presses an actuating lever. Thetissue compressing arms descend, opposing the tissue below the pointsheld in place by the tissue manipulators, and positions the two sides ofthe tissue against one another. The insertion mechanism furthercomprises an actuation arm attached to the insertion device which allowsonly vertical translation synchronized to deploy the insertion devicecarrying one of the fasteners after the tissue is positioned. Thisvertical translation may be driven by electromotive, spring, or manualforce through coupling arms, or other means known in the art for drivingstaples. The final downward position may be constrained by a mechanicalstop adjusted to deploy the fastener to a desired depth in the tissue.In an alternate embodiment, the final downward position is determined bya limiting spring, which is chosen to compress significantly only when aforce comparable to the maximum force to be applied to the insertiondevice to seat the fastener fully within the everted tissue is applied.

Needles of the insertion device do not need to be exposed until thedeployment mechanism is activated, thus the risk of needle sticks to theoperator is minimized. At the completion of the inserting actionsaccomplished by any of the above or other means, the insertion device isretracted leaving the fastener in place in the tissue. Furtherretraction of the actuation mechanism allows the insertion mechanism tobe withdrawn and the tissue compressing arms to reopen. As a final stepof a method to deploy the fastener, the user urges the two sides of thetissue that have been held with the tissue manipulators toward the lineof apposition until the cut surfaces come into contact with one another,and then releases the epidermis.

Indications for the bioabsorbable fastener of the present inventioninclude minimally invasive surgical skin wound closure as well as longerskin wound closure (both surgical and accidental). Also, approximatingother tissues, such as intestines, arteries and veins, or any softtissue apposition in an everted or inverted orientation such asanastamoses, are procedures that would benefit from the presentinvention. While the present invention is described utilizingbioabsorbable materials, it will be appreciated that in somecircumstances many of the benefits of the fastener can be achieved usingnon-bioabsorbable materials.

Accordingly, an aspect of the invention involves a fastener for use inapposing body tissues, said fastener being fabricated from bioabsorbablematerial such as a polyglycolic acid, a copolymer, or a blend ofpolymers. The fastener is formed to have two legs, each leg having aninwardly tapered distal end and barbs oriented to resist dislodgement ofthe fastener after insertion into tissue. The two legs are connected bya flexible bridge at their proximal end and cannulated to receive aninsertion device, which extends through the legs and exits the distalend exposing a sharp point to facilitate insertion of the fastener intotissue.

Another aspect of the invention relates to a method for apposing thetissues in closing a surgical incision or wound utilizing abioabsorbable fastener of the present invention, tissue manipulators,and an insertion device. The method comprises use of tissue manipulatorsto pull upwards and index the two sides to be apposed with respect tocompressing forceps, such procedure being adapted to roll the surfacesof the dermis from a horizontal to a vertical orientation whilecompressing the tissue together. The two sides of the incision or woundare held in this upward facing orientation while the bioabsorbablefastener is inserted from above.

Still another aspect of invention comprises an insertion mechanism ableto carry multiple fasteners of the present invention, at least oneinsertion device having two sharpened needles inserted into thecannulated legs of the fastener to facilitate penetration of the tissue,mechanical means to reference the two sides of the tissue to be apposed,to compress and hold the tissue in a favorable orientation for receivingthe fastener, and a translating mechanism to drive and then retract theat least one insertion device into the tissue thereby leaving thefastener in place.

Disclosed and contemplated embodiments of tissue fasteners, insertionmechanisms, insertion devices, and methods for closing a wound (whethercreated surgically or otherwise) with the fastener, in accordance withthe invention, are different in a variety of ways than known surgicalstaples and related stapler devices. For example, embodiments of tissuefasteners according to the invention are structurally distinct fromknown staples. Also, as another example, the inventive fasteners aredeployed in a distinct way. As yet another example, fasteners accordingto the invention, once deployed into the body hold wounds together bytension.

Other aspects, objects, and advantages of the invention are includedherein even if not expressly called out. The disclosed embodiments areexemplary and not limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. Also, the drawings are notnecessarily to scale, emphasis instead generally being placed uponillustrating the principles of the invention. In the followingdescription, various embodiments of the present invention are describedwith reference to the following drawings, in which:

FIG. 1 shows a typical incision in the skin of the type that may beclosed using the present invention;

FIG. 2 is a cross section of incision shown in FIG. 1 taken along thesection 2-2′;

FIG. 3 a shows the insertion device positioned to be inserted into thelegs of the bioabsorbable fastener of the present invention;

FIG. 3 b shows the bioabsorbable fastener of the present inventionpositioned on the insertion device ready to be deployed;

FIG. 4 a is a cross section of the skin tissue of FIG. 2 raised bypulling upwards using tissue manipulators;

FIG. 4 b is a cross section similar to FIG. 4 a showing the tissuefurther oriented for receiving the fastener of the present invention andthe insertion device with a bioabsorbable fastener ready to be deployed;

FIG. 5 a shows a cross section of skin tissue similar to FIG. 4 b withthe bioabsorbable fastener and insertion device deployed;

FIG. 5 b shows the cross section of skin tissue of FIG. 5 a after theinsertion device has been removed;

FIGS. 6 a and 6 b show the cross section of skin tissue of FIG. 5 bafter the tissue manipulator has been removed and the bridge connectingthe legs of the bioabsorbable fastener has relaxed, for two possibleembodiments of the bioabsorbable fastener;

FIGS. 7 a through 7 e show alternate embodiments of the bioabsorbablefastener;

FIG. 7 f shows a plurality of fasteners molded into an assembly in whichlinked components interconnect the bridges of the fasteners;

FIGS. 7 g, 7 h, and 7 i show assemblies of fasteners and insertiondevices created by an insert molding process;

FIG. 8 shows a cross section of skin tissue similar to FIG. 5 with aspecially adapted compressing forceps compressing the dermal tissues tobe apposed;

FIGS. 9 a through 9 d show the process illustrated in FIGS. 4 and 5implemented with the aid of a mechanism that coordinates the severalsteps;

FIG. 10 shows a modification of the arrangement depicted in FIG. 8, nowequipped with presser feet for approximating the cut surfaces of thetissue to be repaired;

FIG. 11 is a perspective view of an alternate embodiment of a hand-heldinsertion mechanism used to insert the bioabsorbable fastener;

FIG. 12 a shows a cross section of skin tissue as in FIG. 2 in which thecut surfaces of the tissue are raised and reflected over the presserfeet by tissue manipulators, orienting the cut surfaces for receivingthe bioabsorbable fastener, shown mounted on an insertion device;

FIG. 12 b shows the cross section of skin tissue as in FIG. 12 a, withthe bioabsorbable fastener and insertion device deployed and penetratingthrough the dermal layer;

FIG. 12 c shows the cross section of skin tissue as in FIG. 12 b afterthe insertion device has been removed;

FIGS. 12 d and 12 e show the cross section of skin tissue as in FIG. 12c after the tissue manipulators have been removed and the bridgeconnecting the legs of the bioabsorbable fastener has relaxed, FIG. 12 eshowing a fastener with additional axially directed barbs as in FIG. 7b;

FIG. 13 a shows a perspective view of an individual fastener;

FIG. 13 b shows a top view of the fastener of FIG. 13 a;

FIG. 13 c shows a front view of the fastener of FIG. 13 a throughsection A-A of FIG. 13 b, and also shows a partial cutaway view of oneof the legs of the fastener; and

FIG. 13 d shows a side view of the fastener of FIG. 13 a through sectionB-B of FIG. 13 c.

DESCRIPTION

With reference to FIG. 1, an opening 50 in the skin 53 is shown such asmay be caused by an incision or wound. For purposes of this description,the “upward” or vertical direction is that direction generallyperpendicular to the surface of the skin 53, even if that surface iscurved or facing in another direction. Human skin is comprised of layersthat are indicated in FIG. 1 and seen in FIG. 2 which is a cross-sectiontaken along line 2-2′. The outermost layer, the epidermis 56 consists ofmostly dead cells. Below this is found the dermal layer 59 that is athin layer of strong living tissue and then the subcutaneous layer 62.While the present invention will be described with reference to openingsin human skin 53, it will be understood that approximating other tissuessuch as intestines, arteries and veins, or any soft tissue apposition inan everted or inverted orientation such as anastamoses, can benefit fromthe present invention.

In FIG. 2, the line of apposition 65 represents a vertical plane thatruns longitudinally bisecting the opening 50 in the skin 53. Tofacilitate the healing process, the surfaces 68 a and 68 b of the livingdermal layer must be brought together and held in close contact forseveral days.

In FIG. 3 a and FIG. 3 b, the fastener 71 of the present invention ispositioned in relation to the driving end of an insertion device 74. Thefastener 71 is mounted onto the insertion device 74 for purposes ofdeploying the fastener into tissue. The fastener 71 is made frombioabsorbable plastic materials such as polyglycolides and comprises twolegs 77 a, 77 b cannulated to receive the insertion needles 79 a, 79 bof the insertion device 74. In FIG. 3 a, the insertion device 74 isshown aligned for insertion into the fastener 71, while FIG. 3 b showsthe two components fully assembled, as would be the case prior todeployment into tissue. The needles 79 a, 79 b of the insertion device74, when fully inserted in the legs 77 a, 77 b as shown in FIG. 3 b,extend a small distance beyond the distal end of legs 77 a, 77 b toexpose sharp ends 80. The sharp ends 80 facilitate penetration intotissue. The sharp ends 80 can be, for example, tapered similar to atypical pencil point, as shown in FIG. 3 b and other figures. If thesharp ends 80 are tapered, each of them has a centered point, as would asharpened pencil. The sharp ends 80 instead can be, for example, beveledas shown in FIGS. 7 g-7 i. Each leg 77 a or 77 b of the fastener 71 hasat least one barb 83 oriented to resist retraction of the fastener 71after deployment into tissue. The two legs 77 a, 77 b are connected atthe proximal end by a flexible bridge 86.

FIG. 4 a shows the skin 53 being pulled upward by tissue manipulators 91a, 91 b while being urged toward the line of apposition 65 by arms 94 a,94 b. Continued pulling by tissue manipulators 91 a, 91 b as shown inFIG. 4 b and urging by arms 94 a, 94 b causes the surfaces 68 a, 68 b ofthe dermal layer to move from a generally vertical orientation facingeach other, to a generally horizontal one facing upward pulling it awayfrom the subdermal tissue and exposing the underside of the dermallayer. In FIG. 4 b, the insertion device 74 carrying the fastener 71 isshown in the correct orientation prior to inserting the fastener 71 intothe tissue.

FIG. 5 a shows the insertion device 74 with fastener 71 after insertionshowing the entry point for the legs 77 a, 77 b into the under side ofthe dermal layer 59. The displacement 97 indicated for leg 77 b (andsimilar for leg 77 a) is the distance along the underside of the dermallayer 59 from the cut surface 68 b to the insertion point for leg 77 b.This displacement 97 of the insertion point is approximately half thelength of the bridge 86 where it connects the two legs 77 a and 77 b. Wehave found that this insertion technique allows the barbs 83 to engagethe tissue at a depth sufficiently far from the surfaces 68 a, 68 b sothat the bridge 86 can provide a tension holding the tissues togetherafter the insertion device 74 is removed from the fastener 71 as shownin FIG. 5 b.

FIG. 6 shows the tissues of FIG. 5 b after the tissue manipulators 91 a,91 b and arms 94 a, 94 b have been removed. The flexible bridge 86 bendseasily and allows the legs 77 a, 77 b to spread angularly after theinsertion device 74 is removed. A small amount of curvature may remainin the bridge 86, as it is desirable that the tissue be slightly evertedwhere it meets along the line of apposition 65.

FIGS. 7 a through 7 e show alternate embodiments of the fastener 71 ofthe present invention differing principally in the position and numberof barbs 83. The barbs may further lie in any plane that passes throughthe axis of the leg, either to facilitate manufacturing (e.g. usinginjection molding tooling) or to enhance the fastener's retentionstrength in tissue. However, it is desirable that no barb should beplaced such that its pointed element, once the fastener is in place, isdirected upwards towards the skin surface 53. The fastener in FIG. 7 badds axially directed barbs 98 at the top of each leg that cansupplement the retention strength of the other barbs 83 when they areengaged as shown in FIG. 6 b.

While the present description shows the fasteners individually, it willbe understood that they may be placed in an assembly containing aplurality of fasteners held in relation to one another by a cartridgemeans or molded in such an assembly with inter connecting frangibleplastic components 99, as shown in FIG. 7 f. While the inter-connectingcomponents 99 are shown for only one of the alternate embodiments itwill be understood that components 99 can be added to other embodimentsof FIGS. 7 a to 7 e.

To facilitate molding of the fasteners of the present invention eithersingly or in multiples, the legs 77 a, 77 b may be oriented in the openposition similar to that shown in FIG. 7 e with the bridge 86straightened and subsequently bent to the configuration as shown in FIG.7 a prior to deployment.

In one embodiment, fasteners 71 can be made using a manufacturingprocess known as insert molding, as shown in FIGS. 7 g through 7 i.Referring to those figures, the insertion device 74′ is fabricated priorto molding fastener 71. Needles 79′a and 79′b are installed incylindrical shoulders 90 a and 90 b respectively which are part of yoke92. Insertion device 74′ is inserted into a molding cavity in aninjection molding process, and the bioabsorbable polymer is injectedaround it to form fastener 71. FIG. 7 h shows the combination ofinsertion device 79′ and fastener 71 as molded by this process. FIG. 7 ishows how the insert molding process described above can be used in amulti-cavity tool to yield multiple fasteners each connected to anotherby frangible components 99′.

FIG. 8 shows compressing forceps 101 that facilitate insertion of thebioabsorbable fastener of the present invention. The compressing forceps101 have at the distal ends of each arm 103 a, 103 b, half-cylindercomponents 106 a, 106 b with features 109 a, 109 b (indentations orslots) at the top of the half-cylinder components 106 a, 106 b intowhich tissue manipulators 91 a, 91 b can be positioned. The user placesthe compressing forceps 101 so that each cylindrical component 106 a,106 b presses against the skin 53 on either side of the line ofapposition 65 with the axes of the cylinders parallel to incision orwound. Tissue manipulators 91 a, 91 b are used to pinch each side of thetissue to be apposed and pull it upwards indexing the tips of themanipulators in the features 109 a, 109 b at the top of the cylindricalcomponent. The compressing forceps 101 are then squeezed until stoppingelements 112 a, 112 b in the forceps meet to restrict furthercompression. The stopping elements 112 a, 112 b are designed to allowthe tissues to be compressed leaving a predetermined distance of 4-8 mmseparating the inner surfaces of the cylindrical components (dimension Ain FIG. 8). This configuration assures that the cut surfaces 68 a, 68 bof the dermal layer are displaced away from the insertion deviceexposing the underside of the dermal layer and orienting it upwards toaccept the fastener from above. The user deploys the fastener using theinsertion device by penetrating the compressed dermal tissue between thetwo cylindrical components 106 a, 106 b. The compressing forceps 101 mayalso have indexing means to align an insertion device (not shown) sothat it penetrates the underside of the dermal tissue equally spacedbetween the cylindrical components 106 a, 106 b.

FIGS. 9 a-9 d show an insertion mechanism 200 which provides a means fordeploying the fastener 71 from above the skin 53. An alternateembodiment of the fastener 71, described above in FIG. 7 b, is depictedbeing used with the insertion mechanism 200. Accordingly, one methoduses an insertion mechanism 200 in conjunction with tissue manipulators91 a, 91 b, to provide a means to coordinate the relative positions ofthe driving head of the insertion device 74, the tissue compressing arms203 a, 203 b and the dermal layer. The tissue manipulators 91 a, 91 bare manually used to pinch the epidermis 56 and pull upwards on the twosides of the incision. The distal ends of the tissue manipulators 91 a,91 b are then positioned in index cavities 206 a, 206 b which positionsthe cut surfaces 68 a, 68 b of the dermal layer away for the point ofpenetration on either side of the line of apposition 65. The tissuecompressing arms 203 a, 203 b are movably attached to the insertionmechanism 200 as for example, with pivoting elements 209 a, 209 b. Thetissue compressing arms 203 a, 203 b, located on either side of theinsertion mechanism 200, move in unison when the user presses anactuating lever (not shown). At the distal ends of the tissuecompressing arms 203 a, 203 b there are cylindrical elements 213 a, 213b which contact the tissue below the points held in place by the tissuemanipulators 91 a, 91 b, and compress the two sides of the tissueagainst one another. The insertion mechanism 200 further comprises anactuation arm 216 attached to the insertion device 74 which allows onlyvertical translation synchronized to deploy the insertion device 74carrying one of the fasteners 71 after the tissue is compressed. Thisvertical translation may be driven by electromotive, spring, or manualforce through coupling arms, or other means known in the art for drivingstaples. The final downward position may be constrained by a mechanicalstop (not shown) adjusted to deploy the fastener to a desired depth inthe tissue. In an alternate embodiment, the final downward position isdetermined by a limiting spring 219, which is chosen to compresssignificantly only when a force comparable to the maximum force to beapplied to the insertion device to seat the fastener fully within theeverted tissue is applied. If the motive force for the actuation arm 216is manual force the limiting spring 219 can provide force feedback tothe user without appreciably advancing the fastener further into thetissue. This adds a degree of compliance to the mechanism making theexact vertical position of the surfaces 68 a, 68 b of the dermis lesscritical than with a rigid mechanism. In addition, the likelihood oftissue tearing as a result of excessive force applied to the actuationarm 216 is reduced so long as the user remains sensitive to the maximumappropriate force to be applied.

The different steps of a method of the present invention are shown inFIG. 9 a-9 d. In FIG. 9 a, tissue manipulators 91 a, 91 b have pinchedthe epidermis 56 on either side of the wound to be apposed and theinsertion mechanism 200 has been brought into place. The tissuemanipulators 91 a, 91 b have been located to index cavities 206 a, 206 bprovided on the insertion mechanism for this purpose. A fastener 71 hasbeen mounted on the insertion device 74, which is in turn mounted to theactuation arm 216 by means of a shaft 222 that allows only verticaltranslation.

In FIG. 9 b, the actuating arm 216 of the mechanism has started todescend, forcing tissue compressing arms 203 a, 203 b against the edgesof epidermis 56 held by the tissue manipulators 91 a, 91 b. Movement ofthe tissue compressing arms 203 a, 203 b is limited by the engagement ofthe actuating arm 216 such that the cylindrical elements 213 a, 213 bremain separated a predetermined distance between 4 mm and 8 mm asindicated by dimension “B”. The fastener 71 is shown ready to descendwith the insertion device 74 driven by the actuation arm 216 towards theunderside of the dermal layer of the wound.

In FIG. 9 c, the actuating arm 216 of the insertion mechanism 200 hasdescended further than in FIG. 9 b, maintaining the position of thetissue compressing arms 203 a, 203 b while inserting the fastener 71into the tissue with the aid of the sharp ends 80 of the insertiondevice 74. (As indicated previously, the sharp ends 80 can be tapered asshown in FIG. 3 b or beveled as shown in FIGS. 7 g-7 i, to give just twoexamples of the possible shapes of the sharp ends 80.) The limitingspring 219 is compressing, which builds up the force feedback on theuser who is providing the motivating force on the actuation arm withoutappreciably advancing the fastener further into the tissue. The fastener71 is desireably inserted at a point that is displaced from the edge ofthe cut surfaces 68 a, 68 b by a distance C that is approximately halfthe length of the bridge 86 of the fastener 71.

In FIG. 9 d, the actuation arm 216 is shown in a partially retractedposition leaving the fastener 71 in place in the dermal layer 59.Remaining steps, not illustrated, include the further retraction of theactuation arm 216, allowing the tissue compressing arms 203 a, 203 b toreopen, and the insertion mechanism 200 to be withdrawn while the tissuemanipulators 91 a, 91 b momentarily retain the edges of the epidermis56. As a final step the user brings the tissue manipulators 91 a and 91b together along the line of apposition thereby pulling the two sides ofthe dermal layer 59 until the surfaces 68 a, 68 b of the dermal layertouch one another. Since the points of insertion are a distance C fromeach of the surfaces 68 a, 68 b, and the distance of twice C isapproximately equal to the length of the bridge 86, the bridgestraightens and comes into tension at the point where the surfaces 68 a,68 b touch.

In an alternative embodiment, FIG. 10 shows compressing forceps 301having tissue contacting members 306 a and 306 b that are referred toherein as presser feet and which are shown in FIG. 10 in cross section.The presser feet 306 a and 306 b have a lower vertical profile than thehalf-cylinder components 106 a and 106 b of compressing forceps 101 ofFIG. 8, with that height or profile of the presser feet 306 a, 306 bshown in FIG. 10 as “d” where “d” can be, for example, about 1.0 mm.This lower profile allows the cut surfaces 68 a and 68 b of the skintissue to be everted and reflected over the presser feet 306 a and 306 bat a more acute angle than achievable with the arrangements of FIGS. 4,5, 8, and 9. Reflecting the cut surfaces 68 a and 68 b at a more acuteangle exposes the subcutaneous layer 62 of the dermis 59, permitting theinsertion device 74 to insert the fastener 71 perpendicularly withrespect to the plane of the skin surface 53 through the dermis 59 andinto the subcutaneous layer 62.

The presser feet 306 a and 306 b can include surface features 309 a and309 b for engaging the ends of tissue manipulators 391 a and 391 b. Thesurface features 309 a and 309 b can be notches or ridges, for example.By engaging the ends of tissue manipulators 391 a and 391 b, the surfacefeatures 309 a and 309 b help to stabilize the manipulators 391 a and391 b in a fixed position once the cut surfaces 68 a and 68 b of theskin tissue have been elevated and reflected over the presser feet 306 aand 306 b to the extent desired. The presser feet 306 a and 306 b can bemade of any sterilizable metal (such as stainless steel), sterilizableor single use plastic, or other material suitable for use in surgicalinstruments. They can be formed integrally with the arms 303 a and 303 bof the compressing forceps 301, or they can be attached by means of weldjoints, screws, adhesive, and/or snap-fitting connecting members.

The presser feet 306 a and 306 b can be brought into apposition bysqueezing the compressing forceps 301 until the stopping elements 312 aand 312 b make contact. As shown in FIG. 10, a pre-determined gap A′remains between the opposing presser feet 306 a and 306 b when stoppingelement 312 a makes contact with stopping element 312 b. This gap A′ isdesigned to bring the cut surfaces 68 a and 68 b together to the extentnecessary to align fastener leg 77 a with cut surface 68 a, and fastenerleg 77 b with cut surface 68 b, as shown in FIG. 12 a. Gap A′ is largerthan fastener width B′ by about 1.0 mm to ensure that fastener legs 77 aand 77 b reliably penetrate through the dermis 59 and partially into thesubcutaneous tissue 62, as shown in FIG. 12 b. For an embodiment withfastener width B′ of 4.0 mm, the gap A′ can be in the range of about4.05 mm to about 4.15 mm.

With cut surfaces 68 a and 68 b elevated and reflected over the apposedpresser feet 306 a and 306 b, respectively, as shown in FIG. 10, thetissue is then ready to receive an insertion device 74 having a mountedfastener 71. The insertion device can be inserted into the tissue in anumber of ways. For example, an operator can grasp insertion device 74manually with thumb and index finger and advance it generallyperpendicular to the plane or surface of the tissue as shown in FIG. 12a. After depositing the fastener 71 into cut surfaces 68 a and 68 b, theoperator can then withdraw the insertion device 74, as shown in FIG. 12c.

FIG. 11 is a perspective view of a hand-held insertion mechanism 400which can hold and deploy the fastener 71 from above the plane of thetissue 453 (e.g., the skin of a human or other mammal) having the cut orincision. The insertion mechanism 400 is held in a position to place itsinsertion device 74 generally perpendicular to the plane or surface ofthe tissue having the cut or incision, as shown in FIG. 12 a. Theinsertion mechanism 400 can have loaded into it and held internally oneor more of the fasteners 71.

As shown in FIG. 11, the insertion mechanism 400 comprises a pair ofopposing presser feet 406 a and 406 b attached to the insertionmechanism 400 via arms 403 a and 403 b, respectively. Arms 403 a and 403b are spaced apart by gap 412 which is chosen to provide the correct gapA′ between the opposing presser feet 406 a and 406 b. Gap 412 may befixed by the mechanical assembly of the insertion mechanism 400 or inanother embodiment gap 412 can be adjustable by a screw or other meansknow in the art. At least one of the presser feet 406 a and 406 b canhave an angular or curved shape in the horizontal plane, such that thedistal ends of presser feet 406 a and 406 b define a wider lead-in areathat becomes progressively narrower from front to back, as shown in FIG.11. The lead-in area reaches a minimum width which defines gap A′directly beneath the insertion device 74. In order to bring cut surfaces68 a and 68 b into proper alignment for fastener insertion, an operatorcan use tissue manipulators 491 a and 491 b to raise cut surfaces 68 aand 68 b. The operator can then slide insertion mechanism 400longitudinally along the cut, trapping and compressing the cut surfaces68 a and 68 b between the fixed presser feet 406 a and 406 b, as shownin FIG. 11.

Alternatively, arms 403 a and 403 b of the insertion mechanism 400 canmove in response to handles 410 a and 410 b to move presser feet 406 aand 406 b laterally into and out of the operative field. After the cutsurfaces 68 a and 68 b are raised by the tissue manipulators 491 a and491 b, the insertion mechanism 400 can be placed directly over theplanned insertion site with reference to alignment mark 420, and theoperator can move handles 410 a and 410 b through a first distance tocompress presser feet 406 a and 406 b and align the tissue segments.

After the cut surfaces 68 a and 68 b of the skin tissue or other type oftissue are elevated and reflected over the fixed presser feet 406 a and406 b by tissue manipulators 491 a and 491 b, an operator can manuallycompress handles 410 a and 410 b through a second distance, causingdownward movement of the insertion device 74. As the insertion device 74is made to move downward toward the tissue, it exits fastener cartridge416 and penetrates the cut surfaces 68 a and 68 b, depositing fastener71 (not shown). The handles 410 a and 410 b can be spring-loaded, sothat upon release of the handles, the insertion device 74 can retractinto fastener cartridge 416, leaving the embedded fastener 71 behind asshown in FIG. 12 c.

The insertion mechanism 400 also can be configured to accept a pluralityof the fasteners 71 held in fastener cartridge 416. In one embodimenteach fastener 71 is factory installed onto a disposable insertion device74 and the plurality of these assemblies is held in fastener cartridge416. The assemblies of fastener 71 and insertion device 74 can befabricated from separate components, or by an insert molding process asdescribed previously with reference to FIGS. 7 g, 7 h, and 7 i. Theinsertion mechanism 400 operates on the insertion devices one at a timeto deploy the tissue fasteners 71 into the tissue and to store eachinsertion device 74 after deploying its preloaded tissue fastener 71. Inanother embodiment insertion mechanism 400 has one insertion device 74and a plurality of fasteners 71 are positioned within fastener cartridge416. The plurality of fasteners 71 may be individually placed intofastener cartridge or inserted as a molded assembly withinter-connecting frangible components 99, as shown in FIG. 7 f. Thefrangible components 99 can be formed with and made out of the samebioabsorbable material used to form the fasteners 71. This assembly ofbreakaway fasteners provides ease of loading the fasteners 71 into thecartridge 416 and also provides controlled positioning of the fasteners71 to facilitate the mechanical loading of the fastener onto theinsertion device 74 for deployment. Although FIG. 7 f depicts thefrangible components 99 interconnecting the bridge sections 86 of thefasteners 71, the breakaway connecting components 99 can instead, oradditionally, releasably connect together one or more other sections ofadjacent fasteners 71.

The method of deploying fastener 71 into tissue is further explained inFIG. 12 a-12 d. The sequence of steps is similar for an operatormanually inserting individual insertion devices 74 with the aid ofcompressing forceps 301 or using the hand-held insertion mechanism 400.As shown in FIG. 12 a, the low profile of presser feet 306 a and 306 b(or 406 a and 406 b), allows the cut surfaces 68 a and 68 b to be raisedand retracted at an acute angle with respect to the plane of tissue 53.As shown in FIG. 12 b, the acute angle of reflection of the cut surfaces68 a and 68 b allows the needles 79 a and 79 b of insertion device 74 toenter and exit the dermis 59. As shown in FIG. 12 c, as insertion device74 is withdrawn from the tissue, the fastener 71 is left behind in thetissue by virtue of the engagement of barbs 83 of legs 77 a and 77 binto the dermis 59. As shown in FIG. 12 d, upon release of the cutsurfaces 68 a and 68 b and removal of the tissue manipulators 391 a and391 b (or 491 a and 491 b), as well as presser feet 306 a and 306 b (or406 a and 406 b), the cut surfaces 68 a and 68 b relax into anatomicalapposition with one another. The elasticity of the tissue causes the twocut surfaces 68 a and 68 b to exert a distracting force against theembedded fastener 71, causing its legs 77 a and 77 b to spread apart, aprocess facilitated by the flexible bridge 86. As the legs 77 a and 77 bspread apart, the curvature of the flexible bridge 86 is reduced, andthe distracting force places the bridge 86 in tension thereby aligningand holding legs 77 a and 77 b from further separation. The tensilestrength of legs 77 a, 77 b, and bridge 86 acting on the engagement ofbarbs 83 with the dermis 59 holds the tissue in apposition. As shown inFIG. 12 e, incorporating additional barbs 98, for example, can providesupport for apposing the tissue to reduce the likelihood of the tissuereceding to expose the mid-section of bridge 86 under conditions ofincreased distraction force. These conditions can occur, for example inskin that overlies a joint, or that is otherwise subject to frequentstretching (such as facial skin).

An advantage of the fastener 71 is that it functions by placing the legs77 a and 77 b in tension with bridge 86. Various known staples, whethermetal or plastic, hold the tissue in apposition by structural strength,compressive strength, or resistance to deformation. A property ofplastics, such as bioabsorbable materials used in the present invention,is to be significantly stronger in tensile strength than in deformationresistance strength. Thus, for any given distracting force, the fastener71 can be made smaller and less irritating to tissue than knownfasteners.

A perspective view of an embodiment of fastener 71 is shown in FIG. 13a. A top view of fastener 71 is shown in FIG. 13 b. In this embodiment,the distance 85 between lumen 84 a of leg 77 a and lumen 84 b of leg 77b is approximately 2.75 mm. Shown in FIG. 13 c is a front view offastener 71 through section A-A of FIG. 13 b. A partial cutaway view ofleg 77 b is shown, demonstrating the dimensional relationships betweenleg 77 b, lumen 84 b and barb 83. Barb 83, for example, can form anangle 72 of approximately 30 degrees with respect to the long axis ofleg 77 b. In an embodiment, the effective sharpness of barb 83 can begiven by angle 73, which in this case is approximately 25 degrees. Theperpendicular distance 70 of the tip of barb 83 from the surface of leg77 b in this embodiment is approximately 0.6 mm. The amount by which thedistal portion 78 b of leg 77 b tapers inwardly can be determined byangle 75, which in this embodiment is approximately 15 degrees. In thefastener 71 of FIG. 13 c, the overall width 76 of leg 77 b isapproximately 0.8 mm, the diameter 81 of lumen 84 b is approximately 0.3mm, and the radial thickness of the wall of leg 77 b tapers fromapproximately 0.25 mm to approximately 0.075 mm at its tip 78. FIG. 13 dis a side view of fastener 71, through section B-B of FIG. 13 c. In thisembodiment, the overall length 87 of legs 77 a and 77 b is approximately5.25 mm. The cross-sectional rectangular shape of bridge 86 of thisembodiment is also apparent in this view, a shape that contributes tothe lateral flexibility of the bridge. The bridge 86 of FIG. 13 d has avertical thickness 88 of approximately 0.25 mm and a transversethickness 89 of approximately 0.7 mm.

Embodiments of fasteners according to the invention, such as thedisclosed fastener 71, can be manufactured from one or morebioabsorbable materials, such as copolymers of L-Lactide or D,L-Lactide,and Glycolide. Any suitable bioabsorbable material(s) can be used toform the fastener 71, as long as the material(s) can be formed into thefastener 71 and perform as disclosed herein.

The terms bioabsorbable and bioabsorbable material as used herein areintended to include any suitable material(s) for fasteners according tothe invention that hold their shape and are stable outside of the bodybut that degrade, resorb, absorb, erode, and/or otherwise breakdownwithin the body of a patient over time and are eliminated by the body'snormal functions.

A fastener made of a poly(lactic-glycolic) acid (“PLGA”) copolymer, forexample, can have a ratio of L-lactide to Glycolide of from about 10:90to about 95:5 by weight, such as for example 80:20, 82:18, or 85:15.

In some embodiments, the bioabsorbable material used for the fastener 71is a lactide/glycolide copolymer (such as, for example,poly-DL-Lactide-co-Glycolide or “PDLGA”) where the ratio is never lessthan at least 10% of one element and, in a more specific embodiment, isin a range of 60%-70% lactide.

Some of the bioabsorbable materials that could be used to form afastener according to the invention include poly(d1-lactide),poly(1-lactide), polyglycolide, poly(dioxanone),poly(glycolide-co-trimethylene carbonate), poly(1-lactide-co-glycolide),poly(d1-lactide-co-glycolide), poly(1-lactide-co-d1-lactide),poly(glycolide-co-trimethylene carbonate-co-dioxanone), caprolactone,ploydioxane, and/or copolymers of L-Lactide or D,L-Lactide, andGlycolide.

The material used for the fastener 71 could include compositions withnaturally occurring biopolymers such as collagen and elastin, orstainless steel, metal, nylon or any other biocompatible materials inthe case of a non-absorbable fastener, or even various combinations ofsuch materials depending upon the desired application and performance ofthe fastener 71.

Different formulations of bioabsorbable polymers can provide differentstrength versus dissolution profiles. In one embodiment, a bioabsorbablefastener according to the present invention is formed of a polymer, or aformulation of polymers, which provides a tensile breaking strength fromleg 77 a to leg 77 b across bridge 86 of about 3.5 lbs. upon initialdeployment into a patient and maintains that breaking strength at orabove about 2 lbs. for a minimum of about 5 days. A fastener made ofPLGA having a ratio of L-lactide to Glycolide of about 82:18 and havinga bridge of a rectangular cross-section of about 0.25 mm high and about0.8 mm wide can have such force-withstanding properties.

Depending on the type of opening or wound being held together within thebody of the patient with one or more of the fasteners 71 according tothe invention, each of the fasteners 71 will be formed in such a way andof one or more bioabsorbable materials suitable to allow the fastener 71to maintain its structural integrity within the body of the patient forabout 14 days or for a minimum of about 5 days. The specific time ittakes for any particular fastener to be bioabsorbed in any particularapplication within the body of a patient typically will vary and is afunction of the bioabsorbable material(s) used to form the fastener, thefastener's precise shape, the area within the body of the patient wherethe fastener is deployed, and the patient himself or herself.

The disclosed embodiments according to the invention are exemplary andillustrative. The invention is not limited by or only to the disclosedembodiments. Various alternatives, modifications, and combinations notnecessarily expressly described herein in connection with any particulardisclosed embodiments are considered part of this disclosure and withinthe scope of this disclosure.

1. A tissue fastener, comprising: a bridge section including a firstportion and a second portion; a first leg section integral with thebridge section and extending from the first portion of the bridgesection, at least a portion of the first leg section defining a firstlumen extending therethrough such that the first leg section iscannulated; and a second leg section integral with the bridge sectionand extending from the second portion of the bridge section, at least aportion of the second leg section defining a second lumen extendingtherethrough such that the second leg section is cannulated, the bridgesection and the first and second leg sections comprising a single pieceof material.
 2. The tissue fastener of claim 1 wherein the single pieceof material is bioabsorbable.
 3. The tissue fastener of claim 2 whereinthe bioabsorbable material comprises a copolymer.
 4. The tissue fastenerof claim 2 wherein the bioabsorbable material comprises a blend ofpolymers.
 5. The tissue fastener of claim 1 wherein each of the firstand second leg sections includes at least one barb.
 6. The tissuefastener of claim 5 wherein the at least one barb of each of the firstand second leg sections is oriented in a direction away from the surfaceof tissue after the tissue fastener is inserted into the tissue.
 7. Thetissue fastener of claim 5 wherein the at least one barb of each of thefirst and second leg sections is oriented to resist dislodgement fromtissue after the tissue fastener is inserted into the tissue.
 8. Thetissue fastener of claim 1 wherein the bridge section is sufficientlyflexible to allow the first and second leg sections to spread angularlyafter the tissue fastener is inserted into tissue.
 9. The tissuefastener of claim 1 wherein a portion of each of the first and secondleg sections is tapered.
 10. The tissue fastener of claim 1 wherein thebridge section comprises a frangible connector for releasably connectingthe bridge section to another tissue fastener.
 11. A tissue fasteningsystem, comprising: (i) a tissue fastener comprising a bridge sectionincluding a first portion and a second portion, a first leg sectionintegral with the bridge section and extending from the first portion ofthe bridge section, at least a portion of the first leg section defininga first lumen extending therethrough such that the first leg section iscannulated, and a second leg section integral with the bridge sectionand extending from the second portion of the bridge section, at least aportion of the second leg section defining a second lumen extendingtherethrough such that the second leg section is cannulated, the bridgesection and the first and second leg sections comprising a single pieceof material; and (ii) an insertion device for deploying the tissuefastener into tissue.
 12. The system of claim 11 wherein the insertiondevice is utilized to deploy the tissue fastener from above the tissue.13. The system of claim 11 wherein the insertion device is utilized todeploy the tissue fastener generally perpendicular to the tissue. 14.The system of claim 11 wherein the insertion device comprises a firstneedle for insertion into the first lumen of the cannulated first legsection and a second needle for insertion into the second lumen of thecannulated second leg section.
 15. The system of claim 14 wherein thefirst and second needles are substantially parallel to each other.
 16. Atissue fastening system, comprising: (i) a tissue fastener comprising abridge section including a first portion and a second portion, a firstleg section integral with the bridge section and extending from thefirst portion of the bridge section, at least a portion of the first legsection defining a first lumen extending therethrough such that thefirst leg section is cannulated, and a second leg section integral withthe bridge section and extending from the second portion of the bridgesection, at least a portion of the second leg section defining a secondlumen extending therethrough such that the second leg section iscannulated, the bridge section and the first and second leg sectionscomprising a single piece of material; and (ii) an insertion mechanismfor deploying the tissue fastener into tissue, the insertion mechanismincluding an insertion device and the insertion device being utilized todeploy the tissue fastener from above and generally perpendicular to thetissue.
 17. A tissue fastening system, comprising: (i) a tissue fastenercomprising a bridge section including a first portion and a secondportion, a first leg section integral with the bridge section andextending from the first portion of the bridge section, at least aportion of the first leg section defining a first lumen extendingtherethrough such that the first leg section is cannulated, and a secondleg section integral with the bridge section and extending from thesecond portion of the bridge section, at least a portion of the secondleg section defining a second lumen extending therethrough such that thesecond leg section is cannulated, the bridge section and the first andsecond leg sections comprising a single piece of material; (ii) aninsertion device for deploying the tissue fastener into tissue; and(iii) compressing forceps that include first and second arms and each ofthe arms includes a surface for contacting the tissue.
 18. The system ofclaim 17 wherein the first and second arms comprise a pair of movabletissue compressing arms.